Dealing with noroviruses

Basic tips for zapping noroviruses
The Yomiuri Shimbun
Noroviruses can live in the vomit or feces of infected people, but can also lurk in insufficiently heated bivalve shellfish and other foods.

A cotton swab of infected stool is thought to contain more than 100 million viruses, and only 10, if they are strong enough, are necessary to cause an infection. Noroviruses are acid-resistant, and can survive in the stomach’s highly acidic environment.

Some infected patients will experience severe vomiting and diarrhea more than 10 times per day, though most do not develop fevers and symptoms disappear naturally in one or two days. Although the condition rarely becomes serious, elderly people need to be careful, as deaths have occurred due to asphyxiation on vomit or pneumonia from bacteria entering the lungs.

Group infections can occur in medical or care facilities through contact with diarrhea or vomit that gets onto the floor. Without proper sanitation, the virus can attach itself to dust and enter the body through the airways.

Basic prevention involves washing the hands with soap and running water after using the toilet or before eating.

When cleaning up vomit or feces, use a chlorine sanitizer, as alcohol disinfectants are not effective. Towels and other materials used for cleaning should be placed in sealable plastic bags and discarded. Clothes should be washed in water first and then disinfected with chlorine bleach.

Viruses on cooking utensils and food can be killed if they are exposed to water that is at least 85 C for more than one minute.

Infants and elderly people can easily become dehydrated due to diarrhea, and should be constantly administered small amounts of beverages made with salt and sugar, such as sports drinks, to aid absorption.

If a person cannot take liquids orally or has not urinated in six to eight hours, dehydration is likely and the person probably requires medical treatment.

Antidiarrhea medication can sometimes delay recovery by preventing the body from discharging the virus. Even after the symptoms disappear, care is needed because the virus will remain in feces for about one week.

(Jan. 1, 2013) Yomiuri Shimbun

British expert describes as the norovirus as “the Ferrari of the virus world”, see excerpt below from the News Daily Vomiting Larry battles “Ferrari of the virus world”

“Norovirus is one of the most infectious viruses of man,” said Ian Goodfellow, a professor of virology at the department of pathology at Britain’s University of Cambridge, who has been studying noroviruses for 10 years.

“It takes fewer than 20 virus particles to infect someone. So each droplet of vomit or gram of feces from an infected person can contain enough virus to infect more than 100,000 people.”

Norovirus is hitting hard this year – and earlier too.

In Britain so far this season, more than a million people are thought to have suffered the violent vomiting and diarrhea it can bring. The Health Protection Agency (HPA) said this high rate of infection relatively early in the winter mirrors trends seen in Japan and Europe.

“In Australia the norovirus season also peaks during the winter, but this season it has gone on longer than usual and they are seeing cases into their summer,” it said in a statement.

In the United States, the Centers for Disease Control and Prevention (CDC) say norovirus causes 21 million illnesses annually. Of those who get the virus, some 70,000 require hospitalization and around 800 die each year.


Norovirus dates back more than 40 years and takes its name from the U.S. city of Norwalk, Ohio, where there was an outbreak of acute gastroenteritis in school children in November 1968.

Symptoms include a sudden onset of vomiting, which can be projectile, and diarrhea, which may be profuse and watery. Some victims also suffer fevers, headaches and stomach cramps.

John Harris, an expert on the virus at Britain’s HPA, puts it simply: “Norovirus is very contagious and very unpleasant.”

What makes this such a formidable enemy is its ability to evade death from cleaning and to survive long periods outside a human host. Scientists have found norovirus can remain alive and well for 12 hours on hard surfaces and up to 12 days on contaminated fabrics such as carpets and upholstery. In still water, it can survive for months, maybe even years.

Add the fact that norovirus is particularly resistant to normal household disinfectants and even alcohol hand gels, and it’s little wonder the sickness wreaks such havoc in hospitals, schools, nursing homes, cruise ships and hotels.

During the two weeks up to December 23, there were 70 hospital outbreaks of norovirus reported in Britain, and last week a cruise ship that sails between New York and Britain’s Southampton docked in the Caribbean with about 200 people on board suffering suspected norovirus.


The good news, for some, is that not everyone appears to be equally susceptible to norovirus infection. According to Goodfellow, around 20 percent of Europeans have a mutation in a gene called FUT2 that makes them resistant.

For the rest the only likely good news will have to wait for the results of trials of a potential norovirus vaccine developed by U.S. drugmaker LigoCyte Pharmaceuticals Inc, or from one of several research teams around the world working on possible new antiviral drugs to treat the infection.

Early tests in 2011 indicated that around half of people vaccinated with the experimental shot, now owned by Japan’s Takeda Pharmaceutical Co, were protected from symptomatic norovirus infection.

The bad news, virologists say, is that the virus changes constantly, making it a moving target for drug developers. There is also evidence that humans’ immune response to infection is short-lived, so people can become re-infected by the same virus within just a year or two.

“There are many strains, and the virus changes very rapidly – it undergoes something virologists call genetic drift,” Harris said in a telephone interview. “When it makes copies of itself, it makes mistakes in those copies – so each time you encounter the virus you may be encountering a slightly different one.”

This means that even if a vaccine were to be fully developed – still a big ‘if’ – it would probably need to be tweaked and repeated in a slightly different formula each year to prevent people getting sick.

Until any effective drugs or vaccines are developed, experts reckon that like the common cold, norovirus will be an unwelcome guest for many winters to come. Their advice is to stay away from anyone with the virus, and use soap and water liberally.

“One of the reasons norovirus spreads so fast is that the majority of people don’t wash their hands for long enough,” said Goodfellow. “We’d suggest people count to 15 while washing their hands and ensure their hands are dried completely.”  Read more here

(Reporting by Kate Kelland; Editing by Will Waterman)

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